WLAN上VoIP容量提高的新方法

New capacity enhancement scheme for VoIP over WLAN

分析了在IEEE802.11AP覆盖范围内进行VoIP传输时存在于AP和站点间的发送负载非平衡特性,提出了发送负载均衡(TLB)方法来提高可支持的VoIP容量数.通过在AP中将下行的多个小IP语音包封装成一个大的广播语音包进行发送,降低AP下行数据发送的压力,均衡VoIP链路的上行和下行发送之间的负载量.描述了TLB的实现过程,并在NS2网络仿真软件下对其进行仿真验证.理论和实验结果表明TLB方法能在保证时延和丢包率的基础上极大地提高IEEE802.11支持VoIP传输的容量水平.

The transmission load unbalancing between an access point （AP） and stations is firstly analyzed when VoIP services are transmitted in one IEEE 802.11 basic service set （BSS）. A new transmission load balancing （TLB） scheme is proposed to enhance the capacity performance. Through encapsulating numbers of small downlink voice over IP （VoIP） payloads into one large broadcast voice packet for transmission in AP side, TLB can release the transmission tension in AP side and balance the transmission load between stations and AP. The implementation of TLB is presented and simulations in NS2 are done. Analysis and simulation results validate the capacity enhancements of TLB while keeping delay and packet drop rate in a low level compared with the legacy IEEE 802. 11 standard.